1
|
Cai YH, Gopalakrishnan A, Dong Q, Schäfer AI. Removal of strontium by nanofiltration: Role of complexation and speciation of strontium with organic matter. WATER RESEARCH 2024; 253:121241. [PMID: 38377922 DOI: 10.1016/j.watres.2024.121241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 01/22/2024] [Accepted: 01/29/2024] [Indexed: 02/22/2024]
Abstract
Strontium (Sr) removal from water is required because excessive naturally occurring Sr exposure is hazardous to human health. Climate and seasonal changes cause water quality variations, in particular quality and quantity of organic matter (OM) and pH, and such variations affect Sr removal by nanofiltration (NF). The mechanisms for such variations are not clear and thus OM complexation and speciation require attention. Sr removal by NF was investigated with emphasis on the role of OM (type and concentration) and pH (2-12) on possible removal mechanisms, specifically size and/or charge exclusion as well as solute-solute interactions. The filtration results show that the addition of various OM (10 types) and an increase of OM concentration (2-100 mgC.L-1) increased Sr removal by 10-15%. The Sr-OM interaction was enhanced with increasing OM concentration, implying enhanced size exclusion via Sr-OM interaction as the main mechanism. Such interactions were quantified by asymmetric flow field-flow fractionation (FFFF) coupled with an inductively coupled plasma mass spectrometer (ICP-MS). Both extremely low and high pH increased Sr removal due to the enhanced charge exclusion and Sr-OM interactions. This work elucidated and verified the mechanism of OM and pH on Sr removal by NF membranes.
Collapse
Affiliation(s)
- Yang-Hui Cai
- Institute for Advanced Membrane Technology (IAMT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Akhil Gopalakrishnan
- Institute for Advanced Membrane Technology (IAMT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Qilin Dong
- Institute for Advanced Membrane Technology (IAMT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Andrea I Schäfer
- Institute for Advanced Membrane Technology (IAMT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.
| |
Collapse
|
2
|
Pan Y, Garg S, Fu QL, Peng J, Yang X, Waite TD. Copper Safeguards Dissolved Organic Matter from Sunlight-Driven Photooxidation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:21178-21189. [PMID: 38064756 DOI: 10.1021/acs.est.3c07549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2023]
Abstract
Sunlight plays a crucial role in the transformation of dissolved organic matter (DOM) and the associated carbon cycle in aquatic environments. This study demonstrates that the presence of nanomolar concentrations of copper (Cu) significantly decreases the rate of photobleaching and the rate of loss of electron-donating moieties of three selected types of DOM (including both terrestrial and microbially derived DOM) under simulated sunlight irradiation. Employing Fourier transform ion cyclotron resonance mass spectrometry, we further confirm that Cu selectively inhibits the photooxidation of lignin- and tannin-like phenolic moieties present within the DOM, in agreement with the reported inhibitory impact of Cu on the photooxidation of phenolic compounds. On the basis of the inhibitory impact of Cu on the DOM photobleaching rate, we calculate the contribution of phenolic moieties to DOM photobleaching to be at least 29-55% in the wavelength range of 220-460 nm. The inhibition of loss of electrons from DOM during irradiation in the presence of Cu is also explained quantitatively by developing a mathematical model describing hydrogen peroxide (a proxy measure of loss of electrons from DOM) formation on DOM irradiation in the absence and presence of Cu. Overall, this study advances our understanding of DOM transformation in natural sunlit waters.
Collapse
Affiliation(s)
- Yanheng Pan
- School of Civil and Environmental Engineering, The University of New South Wales, Sydney, New South Wales 2052, Australia
- School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510275, China
| | - Shikha Garg
- School of Civil and Environmental Engineering, The University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Qing-Long Fu
- School of Environmental Studies, China University of Geosciences, Wuhan 430078, China
| | - Jianglin Peng
- School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510275, China
| | - Xin Yang
- School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510275, China
| | - T David Waite
- School of Civil and Environmental Engineering, The University of New South Wales, Sydney, New South Wales 2052, Australia
| |
Collapse
|
3
|
Garraud J, Plihon H, Capiaux H, Le Guern C, Mench M, Lebeau T. Drivers to improve metal(loid) phytoextraction with a focus on microbial degradation of dissolved organic matter in soils. INTERNATIONAL JOURNAL OF PHYTOREMEDIATION 2023; 26:63-81. [PMID: 37303191 DOI: 10.1080/15226514.2023.2221740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Bioaugmentation of soils can increase the mobilization of metal(loid)s from the soil-bearing phases. However, once desorbed, these metal(loid)s are mostly complexed to the dissolved organic matter (DOM) in the soil solution, which can restrict their availability to plants (roots mainly taking up the free forms) and then the phytoextraction performances. Firstly the main drivers influencing phytoextraction are reminded, then the review focuses on the DOM role. After having reminding the origin, the chemical structure and the lability of DOM, the pool of stable DOM (the most abundant in the soil) most involved in the complexation of metal(loid)s is addressed in particular by focusing on carboxylic and/or phenolic groups and factors controlling metal(loid) complexation with DOM. Finally, this review addresses the ability of microorganisms to degrade metal(loid)-DOM complexes as an additional lever for increasing the pool of free metal(loid) ions, and then phytoextraction performances, and details the origin of microorganisms and how they are selected. The development of innovative processes including the use of these DOM-degrading microorganisms is proposed in perspectives.
Collapse
Affiliation(s)
- Justine Garraud
- Nantes Université, Université d'Angers, Le Mans Université, CNRS, UMR 6112, Laboratoire de Planétologie et Géosciences, Nantes, France
| | - Hélène Plihon
- Nantes Université, Université d'Angers, Le Mans Université, CNRS, UMR 6112, Laboratoire de Planétologie et Géosciences, Nantes, France
| | - Hervé Capiaux
- Nantes Université, Université d'Angers, Le Mans Université, CNRS, UMR 6112, Laboratoire de Planétologie et Géosciences, Nantes, France
| | | | | | - Thierry Lebeau
- Nantes Université, Université d'Angers, Le Mans Université, CNRS, UMR 6112, Laboratoire de Planétologie et Géosciences, Nantes, France
| |
Collapse
|
4
|
De Vito-Francesco E, Farinelli A, Yang Q, Nagar B, Álvarez R, Merkoçi A, Knutz T, Haider A, Stach W, Ziegenbalg F, Allabashi R. An innovative autonomous robotic system for on-site detection of heavy metal pollution plumes in surface water. ENVIRONMENTAL MONITORING AND ASSESSMENT 2022; 194:122. [PMID: 35075508 PMCID: PMC8786775 DOI: 10.1007/s10661-021-09738-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 12/23/2021] [Indexed: 06/14/2023]
Abstract
Smart monitoring has been studied and developed in recent years to create faster, cheaper, and more user-friendly on-site methods. The present study describes an innovative technology for investigative monitoring of heavy metal pollution (Cu and Pb) in surface water. It is composed of an autonomous surface vehicle capable of semiautonomous driving and equipped with a microfluidic device for detection of heavy metals. Detection is based on the method of square wave anodic stripping voltammetry using carbon-based screen-printed electrodes (SPEs). The focus of this work was to validate the ability of the integrated system to perform on-site detection of heavy metal pollution plumes in river catchments. This scenario was simulated in laboratory experiments. The main performance characteristics of the system, which was evaluated based on ISO 15839 were measurement bias (Pb 75%, Cu 65%), reproducibility (in terms of relative standard deviation: Pb 11-18%, Cu 6-10%) and the limit of detection (4 µg/L for Pb and 7 µg/L for Cu). The lowest detectable change (LDC), which is an important performance characteristic for this application, was estimated to be 4-5 µg/L for Pb and 6-7 µg/L for Cu. The life span of an SPE averaged 39 measurements per day, which is considered sufficient for intended monitoring campaigns. This work demonstrated the suitability of the integrated system for on-site detection of Pb and Cu emissions from large and medium urban areas discharging into small water bodies.
Collapse
Affiliation(s)
- Elisabetta De Vito-Francesco
- Department of Water, Atmosphere, and Environment, Institute of Sanitary Engineering and Water Pollution Control, University of Natural Resources and Life Sciences Vienna (BOKU), Muthgasse 18, 1190, Vienna, Austria.
| | - Alessandro Farinelli
- Department of Computer Science, University of Verona, Ca Vignal 2, 37134, Verona, Italy
| | - Qiuyue Yang
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), UAB Campus, 08193, Bellaterra (Barcelona), Spain
- Materials Science, Department of Chemistry, Universitat Autònoma de Barcelona, Plaça Cívica, 08193, Bellaterra (Barcelona), Spain
| | - Bhawna Nagar
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), UAB Campus, 08193, Bellaterra (Barcelona), Spain
- Laboratory of Physical and Analytical Electrochemistry (LEPA), Ecole Polytechnique Fédérale de Lausanne (EPFL) Valais Wallis, Rue de l'Industrie 17, 440, 1951, Sion, Switzerland
| | - Ruslan Álvarez
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), UAB Campus, 08193, Bellaterra (Barcelona), Spain
| | - Arben Merkoçi
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), UAB Campus, 08193, Bellaterra (Barcelona), Spain
- Catalan Institution for Research and Advanced Studies (ICREA), Passeig Lluís Companys 23, 08010, Barcelona, Spain
| | - Thorsten Knutz
- Go Systemelektronik GmbH, Falunerweg 1, 24109, Kiel, Germany
| | | | - Wolfgang Stach
- Department of Water, Atmosphere, and Environment, Institute of Sanitary Engineering and Water Pollution Control, University of Natural Resources and Life Sciences Vienna (BOKU), Muthgasse 18, 1190, Vienna, Austria
| | - Falko Ziegenbalg
- Department of Water, Atmosphere, and Environment, Institute of Sanitary Engineering and Water Pollution Control, University of Natural Resources and Life Sciences Vienna (BOKU), Muthgasse 18, 1190, Vienna, Austria
| | - Roza Allabashi
- Department of Water, Atmosphere, and Environment, Institute of Sanitary Engineering and Water Pollution Control, University of Natural Resources and Life Sciences Vienna (BOKU), Muthgasse 18, 1190, Vienna, Austria
| |
Collapse
|
5
|
Tahir M, Khan MB, Shahid M, Ahmad I, Khalid U, Akram M, Dawood A, Kamran M. Metal-tolerant Pantoea sp. WP-5 and organic manures enhanced root exudation and phytostabilization of cadmium in the rhizosphere of maize. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:6026-6039. [PMID: 34431061 DOI: 10.1007/s11356-021-16018-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 08/13/2021] [Indexed: 05/15/2023]
Abstract
This study investigated the phytoremediation potential of maize (Zea mays L.) in Cd-contaminated soil through co-inoculation of metal-tolerant plant beneficial rhizobacteria (MtPBR: Pantoea sp. strain WP-5) with organic manures (PM, poultry manure, and BGR, biogas residues). The objectives of this study were to (i) examine comparative efficiency of MtPBR, PM and BGR alone or in combined form to improve maize biomass and physiology and (ii) understand the role of organic acid production in root exudates of maize for Cd accumulation and translocation. Pantoea sp. WP-5 showed organic acid production and tolerance to high Cd concentration (1000 mg L-1), thereby inoculated to maize seeds sown in soil spiked with 75 mg Cd kg-1 soil and 500 g each of the organic manures per pot. The co-inoculation of MtPBR + BGR significantly (P<0.05) increased chlorophyll contents, root/shoot dry weight, photosynthetic rate, stomatal conductance, and relative water contents and decreased electrolyte leakage, malondialdehyde contents, ascorbate peroxidase, and catalase activity in maize over the control treatment. The co-inoculation of MtPBR + BGR produced significantly (P<0.05) higher concentrations of acetic and citric acid (52.7±0.5 and 22.8±0.08 μg g-1 root fwt, respectively) in root exudates of maize, which immobilized Cd within plant roots inferred by the positive relation (root Cd vs. organic acids; R2 = 0.80-0.92) and reduced Cd translocation to shoots inferred by the negative relation (shoot Cd vs. organic acids; R2 = 0.81-0.90). It is concluded that the application of MtPBR + BGR enhanced organic acid induced phytostabilization and accumulation of Cd in roots and restricted its translocation to shoots.
Collapse
Affiliation(s)
- Muhammad Tahir
- Department of Environmental Sciences, COMSATS University Islamabad, Campus, Vehari, Pakistan.
| | - Muhammad Bismillah Khan
- Department of Agronomy, Faculty of Agricultural Sciences and Technology, Bahauddin Zakariya University, Multan, Pakistan
| | - Muhammad Shahid
- Department of Bioinformatics and Biotechnology, Government College University, Faisalabad, 38000, Pakistan
| | - Iftikhar Ahmad
- Department of Environmental Sciences, COMSATS University Islamabad, Campus, Vehari, Pakistan.
- School of Agriculture and Biology, Shanghai Jiao Tong University/Key Laboratory of Urban Agriculture by Ministry of Agriculture of China, Shanghai, 200240, China.
| | - Umaira Khalid
- Department of Agronomy, Faculty of Agricultural Sciences and Technology, Bahauddin Zakariya University, Multan, Pakistan
| | - Muhammad Akram
- Department of Environmental Sciences, COMSATS University Islamabad, Campus, Vehari, Pakistan
| | - Ahmad Dawood
- Department of Agronomy, Faculty of Agricultural Sciences and Technology, Bahauddin Zakariya University, Multan, Pakistan
| | - Muhammad Kamran
- Department of Environmental Sciences, COMSATS University Islamabad, Campus, Vehari, Pakistan
| |
Collapse
|
6
|
Conditions Affecting the Release of Heavy and Rare Earth Metals from the Mine Tailings Kola Subarctic. TOXICS 2021; 9:toxics9070163. [PMID: 34357906 PMCID: PMC8309732 DOI: 10.3390/toxics9070163] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 06/28/2021] [Accepted: 07/07/2021] [Indexed: 11/17/2022]
Abstract
In the Kola Subarctic, a mining industry has developed, which is a source of environmental pollution with heavy metals. The objects of study were the tailings of three large mining enterprises in the region: apatite-nepheline, complex and loparite ores. The geotechnical characteristics were studied, and the granulometric composition of the samples was established. The main minerals that make up the material of ore dressing tailings have been determined. Using inductively coupled plasma mass spectrometry, the content of trace elements, in particular heavy metals and rare earth elements, has been established. The enrichment factor, the geoaccumulation indexes, the potential ecological risk index factor and the potential environmental hazard index have been calculated. Priority pollutants characteristics for specific objects have been identified. It is noted that the finely dispersed material of the tailings of loparite and complex ores is 1.5–3 times enriched in heavy and rare earth metals in comparison with the total material of the tailings. In laboratory conditions, experiments were carried out to simulate the process of interaction of dust particles with soil solutions containing different amounts of dissolved organic matter and at average seasonal temperatures. It was found that a decrease in the pH of the solution and an increase in the amount of organic carbon and temperature lead to the mobilization of heavy and rare earth metals from the tailings.
Collapse
|
7
|
Linnik PN, Zhezherya VA, Osipenko VP. Potential Complexing Ability of Surface Water Organic Matter: I. Role of Various Groups in Metal Ion Binding. RUSS J GEN CHEM+ 2021. [DOI: 10.1134/s1070363220130095] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
8
|
Shi W, Zhang G, Li F, Feng J, Chen X. Two-step adsorption model for Pb ion accumulation at the algae-water interface in the presence of fulvic acid. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 742:140606. [PMID: 32721737 DOI: 10.1016/j.scitotenv.2020.140606] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 05/09/2020] [Accepted: 06/27/2020] [Indexed: 06/11/2023]
Abstract
The effects of fulvic acid (FA) on heavy metal bioaccumulation by algae have been extensively studied, but the quantitative description on its adsorption behavior is not elaborately illustrated. In the study, the two-step adsorption model is firstly proposed to describe the adsorption of Pb by algae in the presence of FA (R2 > 0.984), which is characterized with two-plateaus in the biosorption curves. The first plateau in the curve represents a monolayer adsorption process of free Pb2+; while the second reveals a multilayer adsorption process of Pb-FA binding to those adsorbed Pb by algae, and the bonding material was called as ternary complex of algae-Pb-(FA-Pb). The formation of the ternary complex caused a sharp increase of the amount of adsorbed Pb by algae which was measured by an atomic absorption spectrophotometry, and a decrease of the toxicity of Pb to algae verified with SEM and TEM images. The ternary phase diagram showed FA could participate in the formation of ternary complexes at very low concentration. The study is important for a comprehensive understanding of the metal-microalgae interaction and its biogeochemical cycle in surface waters.
Collapse
Affiliation(s)
- Wen Shi
- College of Environment, Zhejiang University of Technology, Hangzhou 310032, China
| | - Gaoxiang Zhang
- College of Environment, Zhejiang University of Technology, Hangzhou 310032, China
| | - Feili Li
- College of Environment, Zhejiang University of Technology, Hangzhou 310032, China.
| | - Jianru Feng
- College of Environment, Zhejiang University of Technology, Hangzhou 310032, China
| | - Xiujuan Chen
- College of Environment, Zhejiang University of Technology, Hangzhou 310032, China
| |
Collapse
|
9
|
Zhang X, Li B, Deng J, Qin B, Wells M, Tefsen B. Advances in freshwater risk assessment: improved accuracy of dissolved organic matter-metal speciation prediction and rapid biological validation. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 202:110848. [PMID: 32570102 DOI: 10.1016/j.ecoenv.2020.110848] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 05/27/2020] [Accepted: 06/01/2020] [Indexed: 05/28/2023]
Abstract
Speciation modeling of bioavailability has increasingly been used for environmental risk assessment (ERA). Heavy metal pollution is the most prevalent environmental pollution issue globally, and metal bioavailability is strongly affected by its chemical speciation. Dissolved organic matter (DOM) in freshwater will bind heavy metals thereby reducing bioavailability. While speciation modeling has been shown to be quite effective and is validated for use in ERA, there is an increasing body of literature reporting problems with the accuracy of metal-DOM binding in speciation models. In this study, we address this issue for a regional-scale field area (Lake Tai, with 2,400 km2 surface area and a watershed of 36,000 km2) where speciation models in common use are not highly accurate, and we tested alternative approaches to predict metal-DOM speciation/bioavailability for lead (Pb) in this first trial work. We tested five site-specific approaches to quantify Pb-DOM binding that involve varying assumptions about conditional stability constants, binding capacities, and different components in DOM, and we compare these to what we call a one-size-fits-all approach that is commonly in use. We compare model results to results for bioavailable Pb measured using a whole-cell bioreporter, which has been validated against speciation models and is extremely rapid compared to many biological methods. The results show that all of the site-specific approaches we use provide more accurate estimates of bioavailability than the default model tested, however, the variation of the conditional stability constant on a site-specific basis is the most important consideration. By quantitative metrics, up to an order of magnitude improvement in model accuracy results from modeling active DOM as a single organic ligand type with site-specific variations in Pb-DOM conditional stability constants. Because the biological method is rapid and parameters for site-specific tailoring of the model may be obtained via high-throughput analysis, the approach that we report here in this first regional-scale freshwater demonstration shows excellent potential for practical use in streamlined ERA.
Collapse
Affiliation(s)
- Xiaokai Zhang
- Department of Biological Sciences, Xi'an Jiaotong-Liverpool University, Suzhou, Jiangsu, 215123, People's Republic of China; Department of Environmental Science, University of Liverpool, Brownlow Hill, Liverpool, L69 7ZX, United Kingdom
| | - Boling Li
- Department of Biological Sciences, Xi'an Jiaotong-Liverpool University, Suzhou, Jiangsu, 215123, People's Republic of China; Department of Environmental Science, University of Liverpool, Brownlow Hill, Liverpool, L69 7ZX, United Kingdom
| | - Jianming Deng
- Taihu Laboratory for Lake Ecosystem Research, State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, People's Republic of China
| | - Boqiang Qin
- Taihu Laboratory for Lake Ecosystem Research, State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, People's Republic of China
| | - Mona Wells
- Freshwater Ecology Group, National Institute of Water and Atmospheric Research, Dunedin, 9016, New Zealand.
| | - Boris Tefsen
- Department of Biological Sciences, Xi'an Jiaotong-Liverpool University, Suzhou, Jiangsu, 215123, People's Republic of China
| |
Collapse
|
10
|
Pan Y, Garg S, Waite TD, Yang X. Copper Inhibition of Triplet-Induced Reactions Involving Natural Organic Matter. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:2742-2750. [PMID: 29425033 DOI: 10.1021/acs.est.7b05655] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The triplet excited state of natural organic matter (3NOM*) is an important reactive intermediate in sensitizing transformation of a wide range of environmentally relevant organic compounds, but the impact of trace metals on the fate and reactivity of 3NOM* is poorly understood. In this study, we investigate the effect of low concentrations of copper on 3NOM*-mediated oxidation (electron transfer) and energy transfer reactions. The oxidative efficiency of 3NOM* from Suwannee River NOM (SRNOM) and the widely used model triplet sensitizer 4-carboxybenzophenone were determined by measuring the photooxidation of 2,4,6-trimethylphenol (TMP). The pseudo-first-order photooxidation rate constants of TMP decreased markedly in the presence of trace amounts of Cu(II) (25-500 nM) with the decrease associated with the continuous reduction of the oxidation intermediates of TMP (i.e., TMP•(-H)) by the photochemically produced Cu(I). A kinetic model is developed that adequately describes the Cu inhibition effect in TMP photooxidation in irradiated SRNOM solutions. The 3NOM* energy transfer ability was assessed by measuring the isomerization of sorbic acid with the rate of this process markedly retarded in the presence of significantly higher (micromolar) concentrations of Cu(II) than previously used. This result is attributed to (i) decreased formation of high energy 3NOM* due to formation of Cu-NOM complexes and (ii) increased loss of 3NOM* as a result of quenching by Cu. Since 3NOM* is the precursor to singlet oxygen (1O2) formation, the steady-state concentrations of 1O2 also decreased in the presence of micromolar concentrations of Cu(II) with the quenching rate constant of 3NOM* by Cu calculated to be 1.08 × 1010 M-1 s-1.
Collapse
Affiliation(s)
- Yanheng Pan
- School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology , Sun Yat-sen University , Guangzhou 510275 , China
| | - Shikha Garg
- School of Civil and Environmental Engineering , The University of New South Wales , Sydney , New South Wales 2052 , Australia
| | - T David Waite
- School of Civil and Environmental Engineering , The University of New South Wales , Sydney , New South Wales 2052 , Australia
| | - Xin Yang
- School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology , Sun Yat-sen University , Guangzhou 510275 , China
| |
Collapse
|
11
|
Bosire GO, Kgarebe BV, Ngila JC. Experimental and Theoretical Characterization of Metal Complexation with Humic Acid. ANAL LETT 2016. [DOI: 10.1080/00032719.2016.1141415] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|